PbSPbSe

PbSPbSe refers to the binary alloy system formed by lead sulfide (PbS) and lead selenide (PbSe). The composition is commonly represented as PbSxSe1−x, indicating a continuous solid solution between PbS and PbSe across the full composition range.

In terms of structure, both PbS and PbSe crystallize in the rock-salt (face-centered cubic) structure at room temperature. The PbS–PbSe solid solution adopts the same structure, with the lattice parameter varying with composition. Vegard's law provides a reasonable first approximation for how the lattice parameter changes with x, producing a gradual expansion as selenium content increases.

Electronic properties of the end members show that PbS and PbSe are narrow-gap semiconductors. In the alloy, the band gap can be tuned by composition and temperature, generally decreasing with higher Se content. This tunability extends the absorption edge into the infrared, making the material suitable for infrared sensing applications.

Synthesis and growth methods include bulk crystal growth from a melt, Bridgman techniques, and epitaxial approaches such as molecular beam epitaxy or chemical vapor deposition for thin films. The alloy can be doped to modify carrier type and concentration, enabling p-type or n-type behavior depending on the dopants and processing conditions.

Applications of PbS–PbSe alloys arise from their tunable infrared response and transport properties. They are explored for infrared detectors and imaging systems, as well as for thermoelectric devices where narrow band gaps and favorable carrier mobilities are advantageous.

Safety considerations are important, as lead compounds are toxic and require appropriate handling and disposal. See also lead sulfide and lead selenide.